Panel mounting structure for the electrode carrying end of a discharge lamp



Sept. 27, L. E PANEL MOUNTING STRUCTURE FOR THE ELECTRODE CARRYING ENDOF A DISCHARGE LAMP Filed 001;. 6, 1951 IN V EN TOR.-

LEON A. RICE United States Patent Ofiice 2,719,277 Patented Sept. 27,1955 PANEL MOUNTING STRUCTURE FOR THE ELEC- TRODE CARRYING END OF ADISCHARGE LAMP Leon A. Rice, Arcadia, Calif., assignor to ElectricalProducts Corporation, Los Angeles, Calif., a corporation of CaliforniaApplication October 6, 1951, Serial No. 250,145

Claims. (Cl. 3395tl) The present invention relates in general to lampmountings and has more particular reference to bushing structures forreceiving and making electrical connection with the ends of tubulardischarge lamps.

Tubular discharge lamps conventionally comprise sealed glass tubingcontaining a gas or a mixture of gases adapted to become luminescentwhen electrically excited, the lamp being provided with electrodes atits sealed ends for the application of electrical potential for theexcitation of the gas in the tubular glass envelope. The tubularenvelopes of such lamps may be configurated in any desired manner toform letters or other design characters; and the lamps commonly aremounted for display upon usually sheet metal supporting panels, theelectrode carrying portions of the lamp elements extending throughopenings formed in the panel to thus dispose the electrode containingportions of the lamp behind the panel in position for concealedconnection in an electrical lamp energizing circuit disposed rearwardlyof the panel.

It is an important object of the present invention to provide animproved bushing structure for receiving an electrode containing portionof a panel mounted lamp in fashion to insulate the same from the panelat a panel opening through which it extends, including inexpensive meansoperable to connect the so received lamp portion in an electricalcircuit behind the panel.

Another important object is to provide a device of the charactermentioned formed and arranged to inhibit the accumulation of water, iceor sleet at the mounted end of the lamp in position to form anelectrical conducting path between the electrical lamp connection meansand the panel 011 which the lamp is mounted, whereby substantiallyeliminating the possibility of lamp damage or destruction through theestablishment of a short circuit path for lamp energizing power, fromthe lamp connection means to the grounded panel, along a path adjacentthe mounted portions of the lamp.

Another important object is to provide a structure of the charactermentioned, including a grounding element adapted for connection with thepanel, and insulated support means, carried on said grounding element,for carrying lamp connection elements in the structure at a distance,sufiiciently remote from the supported lamp to prevent damage thereto asthe result of establishment of a power short circuit from the lampenergizing elements of the structure to the grounded panel on which itis mounted, along said insulated support means.

A further object is to provide a device of the character mentionedformed without any pockets or cavities in which moisture may accumulateand form nitric acid capable of destroying the metal parts of thestructure as the result of creation of ozone through the operation ofthe mounted lamp.

Another important object is to provide a lamp connection bushingstructure of simple and inexpensive character and embodying novelattaching means facilitating the application of the structure upon aperforated panel, the attaching means being operable entirely from oneside of the panel to mount the structure in position, thereby avoidingthe necessity of employing an operator on both sides of a large panel inmounting the bushing structure.

Another important obiect is to provide an improved latch structure formounting a device of the character mentioned on a support panel, afurther object being to provide a latch structure adapted for operationentirely from one side of a panel in order to secure the device firmlyin mounted position in a panel opening, or to release the device forremoval from the panel.

Another important object is to provide a mounting structure of thecharacter mentioned comprising a preferably glass bushing, aninexpensive formed sheet metal yoke or collar secured on the bushing,and providing means for latching the collar demountably on a mountingpanel in position presenting the bushing in a panel opening, suchfastening means being adapted to electrically connect, and hence ground,the collar on the panel, said collar providing means for supporting aninsulating stem, offset substantially outwardly of the bushing, inposition to carry, at the collar remote end of the stem, an electricalcontact element in line with the axis of the bushing, and hencepositioned to electrically engage an electrode connected ferrule orcontact terminal on the bushing mounted end of a tubular discharge lamp.

The foregoing and numerous other objects, advantages and inherentfunctions of the invention will become apparent as the same is morefully understood from the following description, which, taken inconnection with the accompanying drawings, discloses a preferredembodiment of the invention.

Referring to the drawings,

Figure 1 is a sectional view taken through a panel carrying a tubulargas discharge lamp having an electrode containing end portion extendingin operative position in a connection bushing structure embodying thepresent invention.

Figure 2 is a sectional view taken substantially along the line 2-2 inFigure 1;

Figures 3, 4 and 5 are sectional views taken substantially along thelines 33, 44, and 55, respectively, in Figure 2; and

Figure 6 is an exploded perspective view showing the several parts ofthe device.

To illustrate the invention, the drawings show a bushing structure forreceiving the electrode containing end portion 11 of a gaseous dischargetubular lamp 12 mounted on a support panel 13. The portions of the lamp12 which extend in front of the panel may be carried on conventionalsupport pedestals 14, of any suitable form. Such pedestals may compriseinsulating material such as glass and may be secured on the panel inposition extending outwardly of the forward surface thereof to supportthe tubular lamp in spaced position in front of the panel. An end of thetubular lamp may be bent, as at 15, to provide the end portion 11 inposition extending through a panel opening 16 to dispose said endportion 11 in concealed position behind the panel for connection in alamp energizing power circuit disposed rearwardly of the panel.

Tubular discharge lamps are commonly provided with electrodes 16, sealedin the opposite ends of the lamp element, and electrically connectedwith external connection terminals which may comprise metal caps orferrules 17 mounted on the extremities of the lamp envelope, whereby thelamp may be connected for operation by electrically connecting theferrules 17 in a lamp energizing circuit, the lamps being operated bythe application of electrical power at relative high potential betweenthe electrodes 16 at the opposite ends of the lamp element.

, The present invention provides an improved bushing structure 18 forelectrically isolating the end portion 11 of the lamp from the panel 13where the lamp extends through the opening 16, said bushing structureincorporating connection means 19, supported in and forming a part ofthe bushing structure and adapted for electrical connection with a lampenergizing circuit and with an electrode connected ferrule 17, when thelamp is in mounted position in the bushing structure, said connectionmeans 19, of course, being electrically insulated from the panel 13.

Tubular gaseous discharge lamps are frequently mounted for operation inposition exposed to the weather. As a consequence, rain, snow, sleet,and other forms of moisture, may accumulate upon the lamp, including theend portions 11 thereof, as well as upon the lamp mounting andsupporting structure, including the bushing structure 18. Suchaccumulation of moisture affords an opportunity for the development ofshort circuit conditions between the ferrules 17, which are energized atrelatively high voltage, and the panel structure 13, which is usuallygrounded for the sake of safety. Any substantial accumulation ofmoisture, snow, or sleet, on or around a lamp portion 11, between thepanel 13 and the ferrule 17, may result in the formation of anelectrical conducting pathway along and adjacent the lamp portions 11,and along which pathway power may flow from the ferrule to the groundedpanel 13. Electrical power flowing through such a moisture formed shortcircuit path may develop relatively high temperatures in theneighborhood of the glass envelope portions 11, which may crack underthe influence of such heat with the resultant destruction of the lamp.

Moreover, the operation of gaseous discharge lamps causes theestablishment of electrostatic phenomena, at and along the envelope,including the end portions 11 thereof, and the resultant production ofsubstantial quantities of ozone, in the atmosphere adjacent the lampenvelope. The reaction of such ozone with moisture and atmospheric dirtresults in the production of nitric acid, which, of course, will attackany metal object with which it comes in contact, including the ferrules17 and the power supply means 19 through which the ferrule is connectedwith the lamp energizing circuit. An important object of the presentinvention, accordingly, is to form the bushing structure 13 in fashionwhich will entirely avoid any possibility of the accumulation ofmoisture, snow, or sleet around the lamp portions 11 to thereby not onlyminimize the formation of nitric acid, but also to inhibit arcing alonga conducting path provided by moisture or accumulated snow or sleet, inclose adjacency to the lamp end portions 11.

With these ends in view, the bushing structure 18 comprises a preferablyglass sleeve-like bushing element 20 medially thickened to form aperipheral rim 21 disposed between the opposite ends 22 and 22 of thesleeve, said ends being sized as to external diameter to fit freelywithin the panel opening 16. The internal diameter of the sleeve 20 issuch as to freely receive the lamp portion element in position extendingthrough the sleeve 20 when the same is mounted in the opening 16.

The bushing structure also comprises a preferably formed sheet metalretaining collar 23 adapted to snugly receive the rim 21 of the sleevemember 20, said collar having an inturned marginal flange 24 on one sidethereof adapted to receive one end 22 of the bushing and to engage oneside of the rim 21 to thereby retain the bushing member 20 in thecollar. Means is-provided at the opposite side of the collar forfastening it upon the rim portion 21 of the sleeve member 20, such meanspreferably comprising integral lugs 25 adapted to be bent or crimpedinwardly into position engaging the side of the rim 20 remote from theflange 24.

In order to support the contact means 19 in the bushing structure, thecollar 23 is provided with a preferably integral outstanding web 26projecting substantially radially of the collar 23 and of the centralaxis of the sleeve Cil ' at and outwardly of the rear face of the panel.

member 20, the contact means 19 being supported on one end of a post 27,the opposite end of which is secured on the web 26 at a substantialdistance outwardly of the collar mounted sleeve member 20.

The post 27 preferably comprises glazed ceramic or other suitableelectrical insulating material. For convenience, the post may haverectangular, preferably square, sectional configuration, although, ofcourse, the invention is not necessarily restricted to the particularsectional shape of the post. The post also may be formed with alongitudinally extending internally threaded axial bore 28, the oppositeends of which are preferably countersunk, as at 29. The web 26, at itsouter end, may also be formed with a centrally perforated depression 30in position to fit into the countersunk opening in one end of the post27; the post being secured on the web 26, as by means of a fasteningmember 31, preferably comprising a screw having a shank adapted toextend through the central opening of the depression 30 and tothreadingly engage in the bore 28 of the post, the screw preferablyhaving aconical head adapted to engage and seat in the depression 30. Inorder to prevent the post 27 from turning on the web 26 and therebybecoming loose on the fastening screw 31, the web 26 may be providedwith upstanding flanges 32 outwardly of the depressed portion 30 inposition to engage an adjacent pair of the sides of the post 27, at theweb mounted end thereof.

The connection means 19 may comprise a helical coil 33 of relativelyresilient conductor wire having an end mechanically and electricallyconnected on a formed sheet metal mounting plate 34 having a perforationadapted to receive a threaded stem 35. This stem is adapted forthreading engagement in the bore 28 of the mounting post 27. A pair ofnuts 36 may be provided for threaded engagement on portions of the stem35, which project at the end of the post 27 in order, not only to securethe mounting plate on the post, but also in conjunction with apair ofwashers 37 to allow for the electrical connection of the post and themounting plate 34, as well as the resilient contact element 33, in alamp energizing circuit, a conductor of which may be so connected withthe means 19 by securing the same clampingly between the washers 37 byoperation of one of the nuts 36. In order to prevent the connectionmeans from turning on the post, the mounting plate may be formed withdependent lips 32' in position'to engage an adjacent pair of the sidesof the post 27, at the plate carrying end thereof.

It will be seen that the helical wire contact element 33 is presented inalignment with the axis of the bushing sleeve 20 so that when the bentend portion 11 of a lamp is in mounted position, in the bushingstructure, more or less in coaxial alignment with the axis of thebushing 20, the contact ferrule 17 of the lamp will engage and makeelectrical contact with the member 33; and the parts will beheldtogether in mounted contact-making relationship by the attachment of thelamp 12 on its supporting pedestals 14.

Any suitable or preferred means may be employed for anchoring thebushing structure 18 on the panel 13 in position with the end 22 of thebushing sleeve 29 extending in and projecting through the panel opening16, the remainder of the bushing structure, of course, extending Theinvention, however, contemplates novel and inexpensive attaching meansoperable entirely from the rear side of the panel for the purpose ofattaching, or dismounting, the bushing structure. In this connection, itwill be apparent that attaching means, operable entirely from one sideof the panel, will have considerable value in connection with mountingthe bushing structure on large panels, since it will eliminatethenecessity of employing two persons, one on each side of the panel, inorder to attach the bushing structure.

The novel attaching means may comprise a finger 38 formed preferablyintegrally on and at one side of the collar 23, as at an edge thereof,said finger having a head forming integral oppositely extending ears 39,and a shank 40 of reduced width interconnecting the head of the fingerwith the rim of the collar 23. The collar 23 may also be formed with 21preferably integral outstanding lug 41 at an edge thereof preferablydiametrically opposite the finger 38. The lug 41 may be formed with anelongated slot or opening 42 adapted to slidingly receive the shank 45of a latching finger 44. This latching finger may conveniently comprisea sheet metal stamping forming the shank or bar 45 and having a headproviding oppositely extending ears 46 at one end of the shank. Theopposite end of the shank may be formed with a longitudinal slit 47defining legs 48 at the end of the shank on opposite sides of the slit.The shank 45 may be assembled in the opening 42, and a preferablyhelical spring 49 may be assembled around the shank and the partsretained in assembled position by twisting and bending the legs 48, asshown more especially in Figure 3 of the drawings, to form them asabutments for engaging and retaining one end of the spring 49, theopposite end of the spring bearing upon the back face of the lug 41. Theslot 42 also is preferably formed with a medial enlargement 42'comprising registering notches formed in its opposite sides; and theshank 45 is formed with a necked portion 45' adapted to turn in saidenlargement 42' of the slot, to allow the head of the finger 44 to bepositioned in a plane extending radially of the axis of the bushing 20,and at right angles to the slot 42. The spring 49 is assembled undercompression and will serve to normally urge the head of the fingertoward the lug 41, and to latch the finger in the enlargement 42' whenturned into position extending transversely of the slot 42.

The panel 13 also may be formed with slots 50 and 50 extending outwardlyon opposite sides of the opening 16, said slots extending radially ofthe center of the opening and communicating with said opening at theirinner ends.

The bushing structure 18 may be positioned on the panel from the rearthereof, at the opening 16, by first inserting the finger 38 in the slot50 to engage the ears 39 with the front face of the panel 13 on oppositesides of said slot 50. Thereupon the structure 18 may be turned intoposition with the forward end of the bushing 20 extending in the opening16. This will present the radially latched head of the finger 44 inregistration with the radial slot 50. By inserting the tip of a screwdriver, or similar device, between the spread legs 48, the finger 44 maybe pushed against the influence of the spring 49 to turn the finger 44in order to release the necked portion 45' from latched engagement inthe slot enlargement 42 and to register the ears 46 with the forwardface of the panel at the opposite edges of the slot 50. Upon release ofthe finger 44 in such turned position, the spring 49 will draw theunnecked portion of the shank 45 into the slot 42 as the bushingstructure is drawn to mounted position on the panel. Engagement of theunnecked portion of the shank in the slot 42 will latch the fingeragainst turning movement, thereby locking the bushing on the panel. Whenthe finger 44 is so latched in the slot 50, the spring 49 will serve tohold the parts in latching position, thereby retaining the bushingstructure 18 in centrally mounted, yet readily detachable, position onthe panel.

The bushing structure, however, may be easily disconnected by pushingthe finger, as by means of a screw driver applied in the slit 47 betweenthe legs 48, to register the necked portion 45' with the slotenlargement 42. Thereupon the finger 44 may be turned into radialposition releasing the ears from engagement with the panel on theopposite sides of the slot 50. The bushing structure may then be removedfrom the panel by a reversal of the positioning procedure; and it willbe apparent that the structure 18 may be mounted on and dismounted fromthe panel by operations accomplished entirely from the rear side of thepanel.

It will be seen from the foregoing that the bushing structure 18, notonly provides substantial spacement between the post 27 and the endportions 11 of a lamp mounted therein, but also provides the metal yokestructure 23, which is grounded on the panel, at the lugs 25, when thebushing structure is mounted on the panel. Furthermore, the structureavoids enclosing the end portions 11 of the mounted lamp except Wherethe same extends through the relatively commodious sleeve 20, which islocated sufficiently remotely from the contact making ferrule to assurethat moisture, snow or sleet may not become packed around the lampportions 11 to any extent between the ferrule 17 of the mounted lamp andthe grounded panel. Moisture, snow or sleet will, of course, fall uponthe structure and the lamp mounted therein as the result of naturalprecipitation; and the same may accumulate to some extent within thebushing 20. Such accumulation, however, will be at a point substantiallyremote from the ferrule 17 and the power supply means 19, including thecontact element 33. It is possible also that snow, sleet and moisturemay accumulate to some extent upon the post 27. Should such accumulationoccur to an extent affording a conducting path along the surface of thepost 27, any electrical power flow along such conducting path willbecome grounded directly to the panel through the metal collar or yoke23 at the lugs 25 thereof and, hence, may not travel in dangerousproximity to any portion of the mounted lamp. Snow or moisture fallingdirectly upon the lamp portions 11 will, of course, be immediatelymelted and evaporated by the heat generated and liberated by the lampduring operation.

Since the lamp portions 11 are substantially unenclosed, such evaporatedmoisture will not be retained around and in the vicinity of the lampportions 11, but will be dissipated to circumambient atmosphere.Accordingly, the end portions 11 of the mounted lamp will at all timesremain in substantially dry condition so that the danger ofestablishment of a short circuit power-flow path from the ferrule 17 tothe grounded panel 13, along a path closely adjacent the lamp portions11, or through the sleeve 20, is entirely eliminated in structuresembodying the present invention. Since the structure thus provides forthe maintenance of substantially dry conditions at and around the lampportions 11, it will be obvious that the danger of nitric acidproduction, through the action of ozone on dirt and moisture, will alsobe entirely avoided.

It is thought that the invention and its numerous attendant advantageswill be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several parts without departing from the spirit orscope of the invention, or sacrificing any of its attendant advantages,the forms herein being preferred embodiments for the purpose ofillustrating the invention.

The invention is hereby claimed as follows:

1. A bushing structure for connecting the electrode carrying end of atubular discharge lamp in a lamp energizing power circuit, comprising anassembly adapted for mounting on a lamp supporting panel, at an openingtherein, said assembly including a sleeve element of insulating materialadapted to extend in said opening in position to receive the electrodecarrying end of the lamp in mounted position therethrough, a mountingpost of insulating material and electrical conducting mounting means forsupporting said post and sleeve in spaced apart relationship, includingmeans for securing said mounting means on the panel to anchor thebushing structure thereon and for electrically connecting said mountingmeans with the panel when the bushing structure is in mounted positionthereon, and contact making means adapted for connection with a powersupply circuit and secured 'on said'post in position to makeelectricalcontact with the electrode carrying end portion ofthe'lampwhen thesame is mounted in -position extending axially throughsaidsleeve element.

2. A bushing structure for connecting the electrode carrying end of atubular discharge lamp-in 'alamp'energizing circuit, comprising anassembly adapted "for mounting on a lamp supporting panel, at an openingtherein, said assembly including 'a sleeve'element "of-insulatingmaterial adapted to extend in said opening in position to receive'theelectrode carrying end ofthe'lamp in mounted position therethrough,amounting post 'of insulating material and a sheet metal stampingforming a collar embracing said sleeve element and an outwardlyextending mounting bracket-for said post to'support the same and saidsleeve in spaced apart offset relationship, including meansforconnecting said stamping on and in electrical contact with the panelwhen the bushing structure is in mounted position'thereon, and contactmaking means adapted for connection with apower supply'circuit andsecured on said post, remote from said stamping in position to makeelectrical contact with the electrode carrying end portion of the lampwhen the samev is mounted in position extending axially through saidsleeve element.

3. A mounting structure for connecting the electrode carrying end of atubular discharge lamp in a lamp energizing circuit, comprising anassembly adapted for mounting on a lamp supporting panel, at an openingtherein, said assembly including a sheet metalmember framing a collarand a post mounting bracket outwardly of said collar, a sleeve elementof insulating material secured in said collar and having an end'adaptedto 'extend in said opening in position to receive the electrode carryingend of the lamp in mounted position axially therethrough, a mountingpost of insulating material secured on said bracket in spaced parallelrelation with respect to the axis of said sleeve, mounting means forsecuring the sheet metal member on the panel to mount the bushingstructure thereon, said sheet metal member being formed with lugs forsecuring the sleeve in the collar and for electrically connecting saidmember with the panel when the bushing structure is in-rnounted positionthereon, and contact making means adapted for connection with alpowersupply circuit and secured on said post in position to make electricalcontact with the electrode carrying end portionmountedaxially throughsaid sleeve element.

4. A bushing structure for-connecting the electrode carrying end of atubular discharge lamp in a lamp energizing power circuit, comprising anassembly adapted for mounting on a lamp supporting panel, at an openingtherein, said assembly including a sleeve of insulating material'adaptedto extend in said opening in position to receive the electrode carryingend of the lamp in mounted position therethrough, contact making meansadapted for connection with a power supply circuit, carrying meanssupporting said contact making means on said sleeve in position to makeelectrical contact with the electrode carrying end portion of the lampwhen the same is mounted in position extending axially through saidsleeve, releasable latch means, and support means mounting said latchmeans on said sleeve for securing the bushing structure on said panel,said latch means including a finger on one side of the sleeve and formedfor interfitting engagement in a panel slot onone side of said panelopening, and a spring pressed latch member on the opposite side of thesleeve and formed for releasable engagement'in a panel slot on theopposite side of said opening.

5. A .bushing structure including a sleeve and means for mounting thesame on a panel, at an opening therein sizedto receive the sleeve,comprising a latch finger and means to secure the same on one side ofthe sleeve in position to interlockingly engage with the panel at anattachment station on one sideof said opening, a spring pressedlatch'bar support means carrying said latch bar for longitudinallyshiftable movement on said sleeve, on the side thereof remote from saidfinger, said support means including a web portion formed with a latchbar slot therethrough, said latch bar comprising a fiat finger axiallyslidable in said latch bar slot, in non-turnable fashion throughout aportion of the length of said finger, said finger having a flat headinsertable through an anchingslot formed in said panel on the side ofsaid opening remote from said station, opposed outstanding ears on saidhead, said finger having a neck of restricted width to permit the sameto turn in said latch bar slot to position said ears for engagement withthe panel at the opposed sides of said anchoring slot, when said neck isin registration with said latch bar slot.

6. A bushing structure including a sleeve and means to mount the same ona panel, at an opening therein sized to receive the sleeve, comprising alatch finger on one side of the sleeve for interlockingly engaging thepanel on one side of the opening, means forming a slotted latch guide onthe sleeve, on the side thereof remote from said finger, a latch barlongitudinally movable in said guide between retracted and projectedpositions, spring means normally urging said bar toward retractedposition in said guide, said bar and said guide being formed to preventrotation of the bar in said guide when in retracted position therein,and to permit rotation thereof when in projected position, said barhaving a head insertable through a panel slot, when in projectedposition, said head having opposed outstanding ears and being turnablein'projected position to dispose said ears for engagement with the panelat the opposed sides of said slot to latch the bushing structure on thepanel.

7. A bushing structure including a sleeve and means to mount the same ona panel, at an opening therein sized to'receive the sleeve, comprising alatch finger on one side of the sleeve for interlockingly engaging thepanel onone side of the opening, means forming a slotted latch guide onthe sleeve, on the side thereof remote from said finger, a latch barlongitudinally movable in said guide between retracted and projectedpositions, spring means normally urging said bar toward retractedposition in said guide, said bar and guide being formed to preventrotation of the bar in said guide when in retracted position therein, topermit rotation thereof in projected position and to prevent retractingmovement of the bar from projected position except when in predeterminedrelatively turned position, said bar having a head insertable through apanel slot, when in projected positioned turned from said predeterminedposition, said head having opposed outstanding ears and being turnable,in projected position, to said predetermined turned position, to disposesaid ears for locking engagement with the panel at the opposed sides ofsaid slot, and to allow the spring means to draw the bar to retractednon-turnable position latching the bushing structure on the panel.

8. A bushing structure as set forth in claim 7, wherein the latch guidecomprises an car on the sleeve and formed withan elongated slot having amedial enlargement, the bar comprising a fiat finger formed for sliding,nonturning interfitment in said slot, said bar having a necked-inportion sized for turning movement in said medialenlargement.

9. A'bushing structure as set forth in claim 7, wherein thelatch guidecomprises an ear on the sleeve and formed with an opening, the barcomprising a finger formed for sliding 'movement in said opening andhaving its head at one end of the finger on one'side of the ear and alongitudinal slot defining spaced legs at the head remote end of thefinger on the other side of the ear, said spring means comprising ahelical element encircling the finger and bearing at its opposite endson said ear and on said legs, said legs being outwardly bent to engageand retain an end of the spring means.

10. A mounting structure for connecting the electrode carrying end of atubular discharge lamp in a lamp energizing circuit, comprising abushing assembly adapted for mounting on a lamp supporting panel, at anopening therein, said assembly including a sheet metal member forming acollar, a sleeve element of insulating material secured in said collar,said sheet metal member being formed with lugs for securing the sleevein the collar and for electrically connecting said member with the panelwhen the bushing structure is in mounted position thereon, insulatedmeans on said sheet metal member for supporting a lamp contact in axialalignment with said sleeve, and mounting means for securing the bushingon the panel comprising a latch finger on one side of said sheet metalmember for interlockingly engaging the panel on one side of the opening,means forming a slotted latch guide on the sheet metal member, on theside thereof remote from said finger, a latch bar longitudinally movablein said guide between projected and retracted latching positions, springmeans normally urging said bar toward retracted position, said bar andguide being formed to prevent rotation of the bar when in retractedposition and to permit rotation thereof when in projected position, saidbar having a head insertable through a panel slot when in projectedposition and being turnable to interlockingly engage said head in saidslot and to position the finger for retracting movement to latch thebushing structure on the panel.

References Cited in the file of this patent UNITED STATES PATENTS1,768,042 Ferguson June 24, 1930 1,937,322 Johnson Nov. 28, 19332,020,886 Hammar Nov. 12, 1935 2,205,051 Schmitt June 18, 1940 2,235,640Kresge Mar. 18, 1941 FOREIGN PATENTS 474,328 Canada June 12, 1951

